I am primarily interested in computer security, and in applying human-computer interaction (HCI) and machine learning (ML) techniques to solve computer security problems. I also apply fundamental security techniques to design, and attack modelling and analysis. For example, I have enumerated the attack space for partial passwords and the answers to challenge questions, and I have modelled attacks to implicit smartphone authentication. In 2003, I designed the “account recovery” interface for the Government Online portal, used by more than six million citizens. The results of my research include critical evaluations of current security solutions, the establishment of new security and usability methodologies, and the design of new security techniques. I currently apply these methods and techniques to authentication protocols, and mobile devices and networks, though I am very interested in broader applications of my research.